1. Field of the Invention
The present invention relates to a vehicle control device, which is configured to support an operation of a driver so as to increase an electric power regeneration amount in a vehicle capable of generating a braking force by recovering electric power to an in-vehicle battery.
2. Description of the Related Art
For example, as proposed in International Patent WO2012/053106A1, there is known a drive support device, which is configured to set a target stop position for a vehicle and to issue an instruction to release an accelerator pedal so that the vehicle stops at the target stop position. Moreover, as proposed in Japanese Patent Application Laid-open No. 2015-19521, there is known a vehicle including a regenerative generator, which is configured to set such a deceleration start position as to increase an electric power regeneration amount to be recovered to a battery during deceleration travel up to a target stop position and to decelerate the vehicle at a high deceleration so that a driver can carry out an ecological drive.
There is an upper limit for a charge current that can be supplied to a battery, and hence, on the vehicle including the regenerative generator, a braking force that can be generated by the electric power regeneration is also limited. Upon an emergency braking operation, a required braking force temporarily exceeds the braking force that can be generated by the electric power regeneration, and hence an insufficient amount in the braking force is compensated by a hydraulic friction braking. Thus, a rotational energy of the wheels cannot be used effectively. Therefore, for the ecological drive, it is important not to carry out the emergency braking operation.
In the vehicle proposed in Japanese Patent Application Laid-open No. 2015-19521, when the vehicle approaches the target stop position, the vehicle speed has already substantially decreased, and hence the driver does not need to depress a brake pedal hard before the target stop position. Thus, the emergency braking operation by the driver can be suppressed, and the power can thus be efficiently recovered to the battery, resulting in an increase in fuel consumption performance. The control of increasing the deceleration when the vehicle is decelerating up to the target stop position (increasing the regenerative braking force), thereby increasing the regenerative electric energy in this way, is referred to as regeneration enhancement control.
Incidentally, there is known a vehicle in which a collision avoidance support device is installed. When an obstacle highly likely to collide with the own vehicle is detected by a sensor, e.g., a radar, the collision avoidance support device increases a brake hydraulic pressure generated when the driver depresses a brake pedal as compared to that in a normal state, to thereby generate a large braking force, or automatically generates the brake hydraulic pressure when the driver does not depress the brake pedal. This control of generating the braking force through the brake hydraulic pressure control to support the collision avoidance for the vehicle is referred to as collision avoidance support control.
A case is conceivable in which the regeneration enhancement control and the collision avoidance support control are simultaneously being carried out, and then, the regeneration enhancement control is finished earlier. In this case, the following problem may arise.
The regeneration enhancement control is finished when the own vehicle reaches a target stop position. Moreover, the target stop position is merely a position at which the vehicle is predicted to stop. Therefore, contrary to the prediction, the own vehicle may not stop at the target stop position and continue traveling. For example, a case is considered in which, under a state in which both the regeneration enhancement control and the collision avoidance support control are simultaneously being carried out, the own vehicle does not stop at the target stop position and continues traveling. In this case, the regeneration enhancement control is finished when the own vehicle passes the target stop position during the execution of the collision avoidance support control, and a regenerative braking force that has been applied until the end of the regeneration enhancement control suddenly disappears, resulting in a rapid decrease in the braking force. The collision avoidance support device carries out the collision avoidance support control based on an inter-vehicle distance between the own vehicle and a preceding vehicle (obstacle), a relative speed between the own vehicle and the preceding vehicle, and the like, and thus an unexpected decrease in the deceleration of the own vehicle may adversely affect a determination precision for the collision with the preceding vehicle and the like. Therefore, the execution of the regeneration enhancement control may induce deterioration in performance of the collision avoidance support control.